Department of Obstetrics and Gynecology, Rambam Medical Center, Haifa, Israel.
Department of Obstetrics and Gynecology, Rambam Medical Center, Haifa, Israel.
Am J Obstet Gynecol. 2016 Sep;215(3):382.e1-6. doi: 10.1016/j.ajog.2016.03.032. Epub 2016 Mar 24.
Maternal magnesium administration has been shown to protect the preterm fetus from white- and gray-matter injury, although the mechanism is unknown.
The purpose of the study is to test the following hypotheses: (1) maternal infections/inflammation activate fetal neuronal N-methyl-D-aspartate receptors that up-regulate neuronal nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells pathways; and (2) maternal magnesium sulfate attenuates fetal brain neuronal nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells activation through N-methyl-D-aspartate receptors.
Pregnant rats at embryonic day 16 and embryonic day 18 (n = 6, 48 total) received injections of intraperitoneal lipopolysaccharide 500 μg/kg or saline at time 0. Dams were randomized for treatment with subcutaneous magnesium sulfate (270 mg/kg) or saline for 2 hours prior to and following lipopolysaccharide/saline injections. At 4 hours after lipopolysaccharide administration, fetal brains were collected from the 4 treatment groups (lipopolysaccharide/saline, lipopolysaccharide/magnesium sulfate, saline/magnesium sulfate, saline/saline), and phosphoneuronal nitric oxide synthase, nuclear factor kappa-light-chain-enhancer of activated B cells p65, and chemokine (C-C motif) ligand 2 protein levels were determined by Western blot. An additional group of pregnant rats (n = 5) received N-methyl-D-aspartate-receptor antagonist following the lipopolysaccharide injection to study magnesium sulfate protective mechanism.
Lipopolysaccharide (lipopolysaccharide/saline) significantly increased fetal brain phosphoneuronal nitric oxide synthase, nuclear factor kappa-light-chain-enhancer of activated B cells p65, and chemokine (C-C motif) ligand 2 protein levels compared to the saline/saline group at both embryonic day 16 (phosphoneuronal nitric oxide synthase 0.23 ± 0.01 vs 0.11 ± 0.01 U; nuclear factor kappa-light-chain-enhancer of activated B cells 0.24 ± 0.01 vs 0.14 ± 0.01 U; chemokine (C-C motif) ligand 2 0.28 ± 0.01 vs .01 ± 0.01 U) and embryonic day 18 (phosphoneuronal nitric oxide synthase 0.28 ± 0.01 vs 0.12 ± 0.01 U; nuclear factor kappa-light-chain-enhancer of activated B cells 0.12 ± 0.01 vs 0.1 ± 0.01 U; chemokine (C-C motif) ligand 2 0.27 ± 0.01 vs 0.11 ± 0.01 U). Magnesium sulfate treatment to lipopolysaccharide dams (lipopolysaccharide/magnesium sulfate) significantly decreased fetal brain phosphoneuronal nitric oxide synthase, nuclear factor kappa-light-chain-enhancer of activated B cells, and chemokine (C-C motif) ligand 2 protein levels compared to lipopolysaccharide/saline dams at both embryonic day 16 (neuronal nitric oxide synthase 0.17 ± 0.02 U; nuclear factor kappa-light-chain-enhancer of activated B cells 0.17 ± 0.03 U; chemokine (C-C motif) ligand 2 0.18 ± 0.01 U) and embryonic day 18 (phosphoneuronal nitric oxide synthase 0.1 ± 0.01 U; nuclear factor kappa-light-chain-enhancer of activated B cells 0.09 ± 0.01 U; chemokine (C-C motif) ligand 2 0.21 ± 0.01 U). Notably, maternal lipopolysaccharide at embryonic day 16 activated nuclear factor kappa-light-chain-enhancer of activated B cells twice as often compared to dams induced at embryonic day 18. N-methyl-D-aspartate-receptor antagonist decreased fetal brain phosphoneuronal nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells levels comparable to magnesium sulfate.
Lipopolysaccharide-simulated inflammation during pregnancy may cause brain injury through activation of neuronal nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells pathways and, potentially, production of excitotoxic nitric oxide and inflammatory mediators. The increased susceptibility to brain injury in preterm fetuses may be due to enhanced nuclear factor kappa-light-chain-enhancer of activated B cells activation. Magnesium sulfate protective effects may be secondary, in part, to inhibition of neuronal nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells activation and decrease proinflammatory cytokine production through blocking nuclear factor kappa-light-chain-enhancer of activated B cells receptors.
已经证实，母体镁剂给药可保护早产儿免受白质和灰质损伤，尽管其机制尚不清楚。
本研究旨在验证以下假设：（1）母体感染/炎症激活胎儿神经元 N-甲基-D-天冬氨酸受体，从而上调神经元型一氧化氮合酶和核因子 κB 轻链增强子的 B 细胞途径；（2）母体硫酸镁通过 N-甲基-D-天冬氨酸受体减轻胎儿脑神经元型一氧化氮合酶和核因子 κB 轻链增强子的 B 细胞激活。
妊娠第 16 天和第 18 天的孕鼠（n=6，共 48 只）在 0 时接受腹腔内脂多糖 500μg/kg 或生理盐水注射。将孕鼠随机分为皮下硫酸镁（270mg/kg）或生理盐水治疗组，在脂多糖/生理盐水注射前和注射后 2 小时进行治疗。脂多糖给药后 4 小时，从 4 个治疗组（脂多糖/生理盐水、脂多糖/硫酸镁、生理盐水/硫酸镁、生理盐水/生理盐水）收集胎鼠脑，并通过 Western blot 测定磷酸神经元型一氧化氮合酶、核因子 κB 轻链增强子的 B 细胞 p65 和趋化因子（C-C 基元）配体 2 蛋白水平。另一组孕鼠（n=5）在接受脂多糖注射后接受 N-甲基-D-天冬氨酸受体拮抗剂，以研究硫酸镁的保护机制。
与生理盐水/生理盐水组相比，脂多糖（脂多糖/生理盐水）在妊娠第 16 天（磷酸神经元型一氧化氮合酶 0.23±0.01 比 0.11±0.01U；核因子 κB 轻链增强子的 B 细胞 0.24±0.01 比 0.14±0.01U；趋化因子（C-C 基元）配体 2 0.28±0.01 比 0.01±0.01U）和妊娠第 18 天（磷酸神经元型一氧化氮合酶 0.28±0.01 比 0.12±0.01U；核因子 κB 轻链增强子的 B 细胞 0.12±0.01 比 0.1±0.01U；趋化因子（C-C 基元）配体 2 0.27±0.01 比 0.11±0.01U）显著增加胎鼠脑磷酸神经元型一氧化氮合酶、核因子 κB 轻链增强子的 B 细胞 p65 和趋化因子（C-C 基元）配体 2 蛋白水平。硫酸镁治疗脂多糖孕鼠（脂多糖/硫酸镁）与脂多糖/生理盐水孕鼠相比，在妊娠第 16 天（神经元型一氧化氮合酶 0.17±0.02U；核因子 κB 轻链增强子的 B 细胞 0.17±0.03U；趋化因子（C-C 基元）配体 2 0.18±0.01U）和妊娠第 18 天（磷酸神经元型一氧化氮合酶 0.1±0.01U；核因子 κB 轻链增强子的 B 细胞 0.09±0.01U；趋化因子（C-C 基元）配体 2 0.21±0.01U）显著降低胎鼠脑磷酸神经元型一氧化氮合酶、核因子 κB 轻链增强子的 B 细胞和趋化因子（C-C 基元）配体 2 蛋白水平。值得注意的是，与妊娠第 18 天诱导的孕鼠相比，妊娠第 16 天的孕鼠脂多糖激活核因子 κB 轻链增强子的 B 细胞的频率是其两倍。N-甲基-D-天冬氨酸受体拮抗剂降低胎鼠脑磷酸神经元型一氧化氮合酶和核因子 κB 轻链增强子的 B 细胞水平的作用与硫酸镁相当。
妊娠期间脂多糖模拟的炎症可能通过激活神经元型一氧化氮合酶和核因子 κB 轻链增强子的 B 细胞途径，并可能产生兴奋性一氧化氮和炎症介质，从而导致脑损伤。早产儿易发生脑损伤的原因可能是核因子 κB 轻链增强子的 B 细胞激活增强。硫酸镁的保护作用可能部分是通过抑制神经元型一氧化氮合酶和核因子 κB 轻链增强子的 B 细胞激活以及阻断核因子 κB 轻链增强子的 B 细胞受体减少促炎细胞因子的产生而产生的。
